Configuring interfaces on Cumulus VX

Cumulus Linux is awesome, did you know that? I haven’t got deep in to it, really only looked at bridging so far, but here is how you configure interfaces…so I don’t forget.

Let’s keep it nice and simple. I have two Nokia 7750 VSRs that I want to bridge together, sros3 and sros8. Both have a single connection over port 1/1/1 to the VX switch. These connections are to connect the various VM ports to the VX from the host machines perspective.

What’s this swp stuff? This is what Cumulus will call your interfaces: switchport basically. The management interface of the VX is eth0 and then each connection to a VM is on an swp starting at swp1 and continuing up as needed. Port positioning/numbering is based on the sequence the bridge entries are placed in your VX XML file. The first bridge will be eth0, the second swp1, third swp2 and so on.

My XML config for the 7750s is straightforward enough, nothing fancy going on. This portion connects the VX to sros8 only. You need an entry in your XML file for each port.

swp41 is where sros8 connects and swp43 is where sros3 connects. The .38 is the tag I will accept for this bridge (similar configuration on the VSR). While I don’t need to put an IPv4 address here I can use it to test connectivity between the connected VM and the VX if there is a problem. FYI Cumulus VX comes with Nano as an editor, download VIM as quick as you can. Man I hate Nano 🙂

Boom, super awesome. I really like these bridges, they’re simple enough to install and work with. What we have done is create two bridges, connected each VSR to the VX and then bridged these two host bridges together with sr3_sr8 on the VX. Note the VX has no bridge for sros3_vx2 or sros3_vx1